Purpose of this study is to write a monograph of about 200 pages on the history of the doctrines of the irregular pulse and heartbeat from the time of Galen to the 20th century. This work will be based on a study of both original and secondary sources, and will be illustrated by line drawings of pulse recordings, electrocardiograms and reproductions of important technological aids in the diagnosis of the irregular pulse. Review of the literature shows that a systematic account of the evolution of the concepts of the irregular pulse ad heart beat has not yet been published by other authors. The first part of this monograph will deal with Galen's detailed interpretation of various irregularities of the pulse. Subsequent chapters will analyse the gradual transition from these doctrines to modern ideas under the influence of changing basic concepts, aided by the invention of methods for the mechanical analysis of pulse and heart beat. The study will terminate with the status of this field after the introduction of electrocardiographic recordings of arrhythmias, around 1930.